Smoking article with valve

ABSTRACT

A smoking article having a cylinder of smoking material, a hollow tube within the cylinder of smoking material, and a filter attached to the cylinder of smoking material. The filter includes an upstream segment containing an aerosol former, a downstream segment containing a sorbent material, and a valve positioned between the upstream segment and the downstream segment. The valve has a first position in which the valve is closed and a second position in which the valve is open and allows the passage of smoke through the filter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) to U.S.provisional Application No. 60/906,117, filed on Mar. 9, 2007, theentire content of which is incorporated herein by reference.

SUMMARY

It would be desirable to have a smoking article having a structure whichcontrols the amount of total particulate matter (TPM) in the mainstreamsmoke of a smoking article and/or prevents or limits the migration ofvolatile aerosol formers or other flavorants to other filter components.

In accordance with one embodiment, a smoking article comprises: acylinder of smoking material; a hollow tube within the cylinder ofsmoking material; and a filter attached to the cylinder of smokingmaterial, the filter comprising: an upstream segment containing anaerosol former; a downstream segment containing a sorbent material; anda valve positioned between the upstream and the downstream segments,wherein the valve includes a first position in which the valve is closedand a second position in which the valve is open and allows the passageof smoke through the filter.

In accordance with a further embodiment, a smoking article comprises: acylinder of smoking material; a hollow tube within the cylinder ofsmoking material; and a filter attached to the cylinder of smokingmaterial, the filter having a segment containing an aerosol former, avalve having a first position in which the valve is closed, and a secondposition in which the valve is open and allows the passage of smokethrough the filter, and at least one segment of filtering material.

In accordance with another embodiment, a filter for a smoking articlecomprises: an upstream segment containing an aerosol former; adownstream segment containing a sorbent material; and a valve positionedbetween the upstream segment and the downstream segments, wherein thevalve includes a first position in which the valve is closed, and asecond position in which the valve is open and allows the passage ofsmoke through the filter.

In accordance with a further embodiment, a method of making a smokingarticle, comprises: forming a tobacco rod portion of the smoking articleby placing smoking material between a hollow tube and an outer layer ofwrapper paper; forming a filter portion of the smoking article having aplurality of segments comprising an upstream segment containing anaerosol former, a valve having a first position in which the valve isclosed, and a second position in which the valve is open and allows thepassage of smoke through the filter, and at least one filtering materialsegment; and joining said tobacco rod portion in end-to-end relationshipwith the filter portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a smoking article according to oneembodiment having a tobacco rod with a concentric hollow tube and afilter having a valve.

FIG. 2 is a cross sectional view of a smoking article having a tobaccorod with a concentric hollow tube and a filter having a valve.

FIG. 3 is a cross sectional view of another embodiment of a smokingarticle having a plurality of ventilation holes or perforations on adownstream side of the valve.

FIG. 4 is a cross sectional view of another embodiment of a smokingarticle having a plurality of ventilation holes or perforations on anupstream side of the valve.

FIG. 5 is a cross sectional view of another embodiment of a smokingarticle having a plurality of ventilation holes or perforations about alocation on the tobacco rod.

DETAILED DESCRIPTION

As shown in FIG. 1, a smoking article 10 in the form of a cigaretteincludes a rod 20 of smoking material 21 (FIG. 2), contained in acircumscribing outer wrapper 30. The outer wrapper 30 is typically aporous wrapping material or paper wrapper. The rod 20 is typicallyreferred to as a “tobacco rod” and has a lit end or upstream end 12 anda tipped end 14 at which a filter 40 is attached to the tobacco rod 20.The smoking material 21 is preferably a shredded tobacco or tobacco cutfiller. However, any suitable smoking material 21 can be used.

The smoking article 10 also includes a filter 40 adjacent to the tippedend 14 of the tobacco rod 20 such that the filter 40 and tobacco rod 20are axially aligned in an end-to-end relationship, preferably abuttingone another. The filter 40 has a generally cylindrical shape, and thediameter thereof is essentially equal to the diameter of the tobacco rod20. The ends (i.e., upstream end 16 and downstream end 18 (i.e., mouthend or buccal end) of the filter 40 are open to permit the passage ofair and smoke therethrough.

The filter 40 preferably includes a plurality of filter materials 42,usually circumscribed by a plug wrap or segment wrap 44. The plug orsegment wrap 44 is preferably a paper product which optionallyincorporates a carbonaceous material. The segment wrap 44 maycircumscribe the total length of the filter 40. The filter 40 isattached to the tobacco rod 20 by a tipping paper 50, whichcircumscribes the filter 40 and an adjacent region of the tobacco rod20. The tipping paper 50 is typically constructed of a paper web; but,any suitable material can be used. A ventilated or air diluted smokingarticle 10 can be provided with an air dilution means, such as a seriesof ventilation holes or perforations 52, each of which extend throughthe tipping paper 50 and optionally the segment wrap 44.

FIG. 2 shows a cross sectional view of a smoking article 10 having atobacco rod 20 with a concentric hollow tube 60 and a filter 40 having avalve system 70. The concentric hollow tube 60 can be incorporated intothe tobacco rod 20 of the smoking article 10, in such a way that thetube 60 can alter the usual total particulate matter (TPM) deliveryprofile of a conventional cigarette or smoking article 10. The tobaccorod 20 is comprised of a hollow tube 60, surrounded by a smokingmaterial 21, such as a tobacco filler material, and an outer layer ofcigarette wrapper (paper) 30. The hollow tube 60 is preferably centrallyor concentrically located within the cylindrical rod 20 of smokingmaterial 21, and having a first end 61 on the lit end 12 of the tobaccorod 20, and a second end 63 on the tipped end 14 of the tobacco rod 20.

The hollow tube 60 preferably extends from the tipped end 14 of thetobacco rod 20 towards the lit end 12 of the tobacco rod 20 with anoverall length 64 of about 20 to 100 millimeters. The internal or innerdiameter 66 of the hollow tube 60 can vary from about 0.5 to 5.5millimeters, and is preferably about 1.5 to 3.5 millimeters, and morepreferably about 2.0 to 3.0 millimeters for a tobacco rod 20 with anouter diameter 67 of about 6.0 and 10.0 millimeters and an overalllength 65 of about 40.0 to 125.0 millimeters. It can be appreciated thatone or more non-concentric hollow tubes 60 also can be used. In use, thedelivery profile of the smoking article 10 including the amount of tarper puff will generally be determined by the length 64 and the innerdiameter 66 of the hollow tube 60, as well as the position of hollowtube 60 within the tobacco rod 20.

As shown in FIG. 2, the lit end 12 of the tobacco rod 20 is fully filledtip 68 with a smoking material 21, which extends from the lit end 12 ofthe smoking article 10 to the first end 61 of the hollow tube 60 and hasan overall length 69 of about 2.0 to 30.0 millimeters. It can beappreciated that the length 69 of the fully filled tip 68 of smokingmaterial 21 can vary depending on the length 65 of the tobacco rod 20and the desired delivery profile. The second end 63 of the hollow tube60 is positioned on the tipped end 14 of the tobacco rod 20 adjacent tothe filter 40.

The hollow core tube 60 can be constructed in a number of ways,including a blended tobacco cut filler rod, or other combustiblematerials such as cellulose-based filler, with a hollow center. Thewalls 62 of the hollow tube 60 can be made out of combustible sheetmaterial such as paper, chemically treated paper, and tobacco-basedsheet materials. The sheet materials of the hollow tube 60 can bechemically treated with burn modifiers, ammonium mono-phosphate,flavorants and aerosol formers. Alternatively, the hollow core or tube60 of the tobacco rod 20 can be molded, extruded or formed ofcombustible materials such as blended tobacco or cellulose-basedmaterials using suitable binders such as pectin, starch, and guar gum.In addition, it can be appreciated that the hollow tube 60 can beconstructed to collapse upon itself during use or alternatively,constructed in a manner wherein the hollow tube 60 does not collapseupon itself during use.

As shown in FIG. 2, the filter 40 includes a first or upstream segment72 containing an aerosol former 74, a second or downstream segment 76containing a sorbent material 78, and a valve 70 positioned between theupstream and downstream segments 72, 76. The filter 40 also preferablyincludes at least one segment of a filtering material 42, and morepreferably an upstream and a downstream segment 80, 82 of filteringmaterial 42 surrounding the downstream segment 76 of sorbent material78. Herein, the “upstream” and “downstream” relative positions betweenfiltering material 42 and other features are described in relation tothe direction of mainstream smoke as it is drawn from the hollow tube 60of the tobacco rod 20 and through the multi-component filter 40.

The aerosol former 74 is preferably a glycerin, propylene glycol,triacetin, propylene carbonate and triethyl citrate or other suitablematerial and more preferably propylene glycol. It can be appreciatedthat the upstream segment 72 for the aerosol former 74 can be made offibrous materials such as crimped paper, modified celluloses, felts andfoams, cross-linked polyacrylamide, hydrogels, or suitable material.Additionally, the upstream segment 72 containing the aerosol former 74can be treated with hydrophobic substances such as waxes and paraffin toreduce loss of aerosol former 74 by evaporation during extended storage.

As described herein, the delivery profile of the smoking article 10including the amount of tar per puff will generally be determined by thelength 64 and the internal diameter 66 of the hollow tube 60, as well asits position within the tobacco rod 20. In addition, the amount of tarper puff is also determined by the amount of aerosol former 74incorporated into the smoke when heat is transferred to the upstreamsegment 72 containing aerosol former 74. The amount of aerosol former 74transferred to the smoke will typically depend on the amount of energytransported to the upstream segment 72 and the nature of the aerosolformer 74. In addition, the amount of energy transferred can also bedependent on the geometry of the hollow tube 60, including the length 64and internal diameter 66, and position of the hollow tube 60 within thetobacco rod 20, as well as the puff duration and volume.

The valve 70 includes a first position, wherein the valve 70 is closedand prevents a passage of smoke or other components through the valve70, and a second position, wherein the valve is open and allows thepassage of smoke through the filter 40. The valve 70 can be a one-wayvalve designed to open when a small amount of suction is applied andwhich remains open as long as a minimum operational pressure (or drawrate) is maintained. Alternatively, the valve 70 can be a check valve orother suitable valve arrangement having a pre-determined range ofoperational pressures, wherein the valve opens at a minimum operationalpressure and closes if the applied (draw rate) is higher than a maximumor upper operational pressure.

In a conventional cigarette, a smoker can take puffs of any desiredvolume or duration, which exposes him or herself to variable amounts oftobacco smoke. This phenomenon is often described as compensation orelasticity; i.e., the smoker's ability to draw an uncontrolled amount oftobacco smoke depending on puff volume, duration and frequency. However,the presence of the valve 70 can minimize compensation or elasticity byregulating the maximum amount of tobacco smoke that the smoker isexposed per puff by introducing an upper limit to puff volume.Accordingly, the valve 70 can include a lower (or minimum operationpressure) and an upper (or maximum operation pressure) limitation ofoperation, which limits the maximum puff volume. Alternatively, if thesmoker draws on the cigarette or smoking article 10 at a flow or drawrate greater than the upper limitation of operation, the valve 70 canlimit the maximum smoke volume per puff, by displacing the excess flowof smoke towards a secondary path (not shown) and providing smoke freeair via a plurality of ventilation holes and/or perforations 52.

In addition, the valve 70 can be a physical or mechanical barrier, whichisolates the tobacco rod 20 and/or aerosol former 74 from the segments80, 82 of filtering material 42 within the filter 40. In addition, sincemany aerosol formers 74 are volatile enough to evaporate duringprolonged storage, the valve 70 can prevent the migration of the aerosolformer 74 to other cigarette filter components, especially to thesorbent material 78. The valve 70 can also increase the shelf life ofthe smoking article 10 by isolating the volatile aerosol formers 74and/or flavorants (not shown) from the filtering material 42. It can beappreciated that generally the valve 70 will be closed and acting aphysical or mechanical barrier, when the cigarette or smoking article 10is not lit, or when the draw rate or operational pressure is minimal,for example, when the smoking article 10 is not being puffed.

The valve 70 can also be used as an internal component of anelectrically heated smoking system and/or a capillary aerosolapplication to regulate TPM delivery and puff volumes, includingregulating the amount of nicotine per puff. Examples of an electricallyheated smoking system are shown in commonly assigned U.S. Pat. Nos.5,388,594 and 5,692,525, which are incorporated herein by reference.Alternatively, the valve 70 can be placed in cigarette holders to beused in conjunction with conventional cigarettes, wherein the valve 70limits the maximum puff volume with the advantage of being used for thelike of cigarette holders leading to a lower cost cigarette or smokingarticle 10.

The downstream segment 76 preferably includes a sorbent material 78 inthe form of an activated carbon filter. As shown in FIG. 2, the sorbentmaterial 78 is positioned between a pair of segments 80, 82 (i.e., anupstream and downstream segment) of filtering material 42. The filteringmaterial 42 is preferably a cellulose acetate tow filter; however, othersuitable filtering materials can be used.

The sorbent material 78 can be in the form of granules, carbon-on-tow(i.e., cellulose acetate with an activated carbon mixed throughout) andthe like. In one embodiment, the sorbent material 78 is a high surfacearea, activated carbon, for example, a coconut shell based carbon oftypical ASTM mesh size used in the cigarette industry or finer.Alternatively, the sorbent material 78 can be a bed of activated carbon,which is adapted to adsorb constituents of mainstream smoke,particularly, those of the gas phase including aldehydes, ketones andother volatile organic compounds, and in particular 1, 3 butadiene,acrolein, isoprene, propionaldehyde, acrylonitrile, benzene, toluene,styrene, acetaldehyde, and hydrogen cyanide. With respect to the carbonparticles, it is preferred that they have a mesh size of from 10 to 70,and more preferably a mesh size of 20 to 50. It can be appreciated thatany suitable sorbent material 78 can be used.

Upon lighting of the smoking article 10, the mainstream smoke isgenerated by and drawn from the tobacco rod 20 and through the filter40. The heat from the tobacco rod 20 is convectively transferred withthe smoke from the lit end 12 of the tobacco rod 20 of smoking material21 through the hollow tube 60 to the tipped end 14 of the tobacco rod 20of smoking material 21 in each puff. It can be appreciated that thesmoke from a smoking article 10 having a hollow tube 60 can travel downthe hollow tube 60 at temperatures as high as 250 degrees C., even atconsiderable distances from the lit end 12. Accordingly, the upstreamsegment 72 having an aerosol former 74, wherein the aerosol former 74 isreleased by exposure to thermal energy contained within the filter 40.The upstream segment 72 having an aerosol former 74 acts as a heat sink,which prevents the filtering material 42 (typically cellulose acetate)from melting under the heat delivered by the hollow tube 60.

FIG. 3 shows a cross sectional view of another embodiment of a smokingarticle 10 having a plurality of ventilation holes or perforations on adownstream side of the valve 70. As shown in FIG. 3, the smoking article10 can have a plurality of ventilation holes or perforations 52, each ofwhich extends through the tipping paper 50 and the plug wrap 44, toprovide the smoking article 10 with filter ventilation. As shown in FIG.3, ventilation of mainstream smoke can be achieved with acircumferential row or rows of ventilation holes or perforations 52about a location along the filter 40. The filter 40 can include aplurality of ventilation holes or perforations 52 on either thedownstream (FIG. 3) and/or the upstream side (FIG. 4) of the valve 70.The ventilation holes or perforations 52 extend through the tippingpaper 50 and the segment wrap 44.

In use, as shown in FIG. 3, the valve 70 can be located upstream of theperforations 52. As the flow rate through the valve 70 increases, itpressure drop increases, thereby forcing more flow through theperforations 52 within the filter 40. Alternatively, the valve 70 caninclude a spring loaded plate or other suitable mechanism (not shown)that moves as the flow rate increases, exposing more perforations, andthereby allowing more flow through the perforations 52.

FIG. 5 shows a cross sectional view of another embodiment of a smokingarticle 10 having a tobacco rod 20 with a plurality of ventilation holesor perforations 52 on the tobacco rod 20. As shown in FIG. 5, thesmoking article 10 can have a plurality of ventilation holes orperforations 52, each of which extends through the wrapper 30 of thetobacco rod 20 providing the smoking article 10 with tobacco rodventilation.

In accordance with an embodiment, the valve 70 can be placed inside atubular segment of a low-density cellulose acetate tow (sometimesreferred to as a hollow acetate tube or HAT). It can be appreciated thatfor ease of manufacturing on high-speed filter rod making equipment, theouter diameter of the valve 70 is less than that of the originaldiameter of the tubular segment prior to filter 40 making operations.Preferably, the diameter of the valve 70 is smaller than thepre-determined diameter of the cigarette to be made. For example, for asmoking article 10 having a circumference of approximately 24.1 mm, thecircumference of the valve 70 is preferably, approximately 23.9 mm orless. As is typically done in established filter making techniques, theoriginal diameter of the hollow acetate tow segment is slightlyoversized so that it may be uniformly compressed into the desireddiameter (e.g. 24.1 mm circumference) during filter making operationsand held by application of segment or plug wrap 44.

It will be understood that the foregoing description is of the preferredembodiments, and is, therefore, merely representative of the article andmethods of manufacturing the same. It can be appreciated that manyvariations and modifications of the different embodiments in light ofthe above teachings will be readily apparent to those skilled in theart. Accordingly, the exemplary embodiments, as well as alternativeembodiments, may be made without departing from the spirit and scope ofthe articles and methods as set forth in the attached claims.

1. A smoking article comprising: a cylinder of smoking material; ahollow tube within the cylinder of smoking material; and a filterattached to the cylinder of smoking material, the filter comprising: anupstream segment containing an aerosol former; a downstream segmentcontaining a sorbent material; and a valve positioned between theupstream and the downstream segments, wherein the valve includes a firstposition in which the valve is closed, and a second position in whichthe valve is open and allows the passage of smoke through the filter. 2.The smoking article of claim 1, wherein the valve is designed to open ata minimum operational pressure and remains open as long as the minimumoperational pressure is maintained; or the valve has a predeterminedrange of operational pressures, and the valve opens at a minimumoperational pressure and closes if the operational pressure is higherthan a maximum operational pressure.
 3. The smoking article of claim 1,wherein the sorbent material is an activated carbon material.
 4. Thesmoking article of claim 1, wherein the upstream and the downstreamsegments are cellulose acetate tow.
 5. The smoking article of claim 2,wherein the sorbent material comprises an activated carbon compositionmixed with cellulose acetate fibers.
 6. The smoking article of claim 1,wherein the aerosol former is selected from a group comprising glycerin,propylene, glycol, triacetin, propylene carbonate and triethyl citrate.7. The smoking article of claim 1, wherein the upstream segment is afibrous material; and the downstream segment of sorbent material isbetween a pair of segments of cellulose acetate tow.
 8. The smokingarticle of claim 7, wherein the fibrous material is selected from agroup comprising crimped paper, modified celluloses, carbon felts andfoams, or encapsulated aerosol formers.
 9. The smoking article of claim1, further comprising a plurality of ventilation holes within the filteron a downstream side of the valve.
 10. The smoking article of claim 1,further comprising a plurality of ventilation holes within the filter onan upstream side of the valve.
 11. A smoking article comprising: acylinder of smoking material; a hollow tube within the cylinder ofsmoking material; and a filter attached to the cylinder of smokingmaterial, the filter having a segment containing an aerosol former, avalve having a first position in which the valve is closed, and a secondposition in which the valve is open and allows the passage of smokethrough the filter, and at least one segment of filtering material. 12.The smoking article of claim 11, wherein the valve is designed to openat a minimum operational pressure and remains open as long as theminimum operational pressure is maintained.
 13. The smoking article ofclaim 11, wherein the valve has a pre-determined range of operationalpressures, and the valve opens at a minimum operational pressure andcloses if the operational pressure is higher than a maximum operationalpressure.
 14. The smoking article of claim 11, further comprising aplurality of ventilation holes within the filter on a downstream side ofthe valve; or a plurality of ventilation holes within the filter on anupstream side of the valve
 15. A filter for a smoking articlecomprising: an upstream segment containing an aerosol former; adownstream segment containing a sorbent material; and a valve positionedbetween the upstream segment and the downstream segments, wherein thevalve includes a first position in which the valve is closed, and asecond position in which the valve is open and allows the passage ofsmoke through the filter.
 16. The filter of claim 15, wherein the valveis designed to open at a minimum operational pressure and remains openas long as the minimum operational pressure is maintained.
 17. Thefilter of claim 15, wherein the valve has a pre-determined range ofoperational pressures, and the valve opens at a minimum operationalpressure and closes if the operational pressure is higher than a maximumoperational pressure.
 18. The filter of claim 15, wherein the smokingarticle is an electrically heated smoking system.
 19. The filter ofclaim 15, wherein the smoking article comprises a cigarette holder and acigarette.
 20. A method of making a smoking article, comprising: forminga tobacco rod portion of the smoking article by placing smoking materialbetween a hollow tube and an outer layer of wrapper paper; forming afilter portion of the smoking article having a plurality of segmentscomprising an upstream segment containing an aerosol former, a valvehaving a first position in which the valve is closed, and a secondposition in which the valve is open and allows the passage of smokethrough the filter, and at least one filtering material segment; andjoining said tobacco rod portion in end-to-end relationship with thefilter portion.